You've been losing weight steadily for months, and then it stops. The scale doesn't move for weeks. You're still taking the medication, still eating less — so what's going on? Weight loss plateaus are one of the most common and frustrating experiences during GLP-1 treatment, and they're almost always normal.
Why plateaus happen
When you lose weight, your body adapts. This isn't a failure — it's biology:
Your metabolic rate decreases. A lighter body requires fewer calories to function. The deficit that was producing weight loss at 100kg may be close to maintenance at 85kg. Your body is burning less energy simply because there's less of it.
Hormonal adaptation. As you lose weight, levels of hormones that regulate hunger (like leptin and ghrelin) shift to encourage your body to defend its new, lower weight — or in some cases, to try to regain lost weight. Even GLP-1 medications don't completely override these adaptations.
Portion drift. Over months of treatment, it's natural for portion sizes to gradually increase as your body adapts to the medication's appetite-suppressing effects. You may be eating slightly more than you were at peak appetite suppression without realising it.
Is the medication still working?
Almost certainly, yes. A plateau doesn't mean the medication has stopped working — it means it's maintaining your reduced weight. Without the medication, your appetite would return to pre-treatment levels and you'd likely regain. The medication is doing its job; it's just that your body has reached a new equilibrium.
What you can do
1. Talk to your prescriber about dose adjustment
If you haven't reached the maximum dose, increasing may restart weight loss. Mounjaro goes up to 15mg and Wegovy up to 7.2mg — if you're on a mid-range dose, there may be room to go higher. Your prescriber will advise based on your response and side effect tolerance.
2. Review your diet honestly
After months on medication, dietary habits can drift. Consider tracking your food intake for a week — not to obsess over calories, but to identify whether portion sizes have crept up, whether liquid calories (alcohol, sugary drinks, coffees with syrups) are contributing more than you think, or whether protein intake has dropped (which affects satiety and muscle maintenance).
3. Add or increase exercise
If you haven't been exercising, starting can restart weight loss. If you have been, changing your routine can help — your body adapts to repetitive exercise just as it adapts to calorie restriction. Adding resistance training is particularly effective because building muscle increases your resting metabolic rate.
4. Check the bigger picture
A plateau of 2–4 weeks is normal and doesn't require intervention. Weight also fluctuates due to water retention, hormonal cycles, sodium intake, and bowel regularity. Look at the trend over months, not individual weeks. If you've been on a genuine plateau (no loss) for 6+ weeks at maximum dose with good adherence, that's when to discuss with your prescriber.
5. Consider whether this is your body's "settling point"
Not everyone will reach the average weight loss seen in clinical trials. If you've lost 15% of your body weight and plateaued, that's a clinically significant and health-improving result — even if the trial average was 22%. Your body may have reached its natural settling point on this medication, and that's okay.
When to be concerned
A plateau is different from weight regain while still on medication. If you're actively gaining weight despite consistent medication use, dietary adherence, and no changes to other medications, discuss this with your prescriber. It could indicate a need for dose adjustment, a switch to a different medication, or investigation of other factors affecting your weight.